This invention relates to a bearing means and more particularly to a cooling device for a bearing means.
One such cooling device for a bearing means of this kind, such as for a machine tool which, publicly known is shown in FIG. 1 of the attached drawings. In FIG. 1 the reference numeral 1 designates the main shaft of a machine tool, which is journalled in bearings 2 such as ball bearings in a front bearing support 3 and a rear bearing support 4, and the shaft 1 being driven by a pulley 5 driven externally through belts by an electric motor (not shown). The machine tool has frame 6 on which are mounted main shaft 1, bearings 2, bearing supports 3 and 4, and pulley 5, frame 6 being mounted on a bed 7 together with the machine parts 1 to 5 as above mentioned.
The operation of the machine tool comprising these elements is as follows:
The torque transmitted to pulley 5 through the belts from the electric motor rotates main shaft 1. In this case bearings 2 disposed between main shaft 1 and front and rear bearing supports 3 and 4 are for the purpose of maintaining a smooth rotation of main shaft 1, but they inevitably generate heat due to rolling friction, as a result of which bearing supports 3 and 4 have their temperature raised by heat conveyed from bearings 2 so that they are subject to various deformations and strains. Consequently, the center line of main shaft 1 of the machine tool may displace in the vertical, horizontal or axial directions as the case may be, reducing the machining accuracy of a workpiece being machined by the machine tool.